Tweaked the README to be a bit more friendly and detailed

I thought the README could use some love, so I added some details about licensing and also detailed out procedures for downloading and building the project.

In addition I added a bit to the "What do you get" paragraph and tried to tighten it all up some.
This isn't hand-holding, it's clarity. In my experience doing this - which is rather lengthy - you can't assume what your users will know or don't and it *doesn't hurt a single thing* to be clear.